The present invention relates to a determination method, in particular to a method, based on immunoassay, for the determination of water treatment chemicals in aqueous media, and to novel antibodies and hybridomas useful in the new method.
The majority of natural waters, and aqueous systems in general, contain dissolved salts of metals such as calcium, magnesium, barium and strontium. When the natural water or aqueous system is heated, the dissolved salts may be converted to insoluble salts, and thereupon deposited as scale on any heat transfer surfaces in contact with the water or aqueous system. Insoluble salt scale may be formed even when the water or aqueous system is merely concentrated, without being heated.
Such precipitation and scale deposition are troublesome and can result in an increase in the costs required to maintain aqueous systems in good working order. Among the problems caused by scale deposits are obstruction of fluid flow, impedance of heat transfer, wear of metal parts, shortening of equipment life, localised corrosion attack, poor corrosion inhibitor performance and unscheduled equipment shutdown. These problems can arise, e.g. in any circulating water system such as those used in oil drilling wells, steam power plants, water desalination plants, reverse osmosis equipment, heat exchange equipment and equipment concerned with the transport of products and by-products in aqueous media, e.g. fly-ash formed during the combustion of coal, in the production of electricity.
A number of additives, notably polycarboxylates, have been provided as effective scale inhibitors for addition to aqueous systems.
Likewise, natural waters and aqueous systems are corrosive towards metals which are in operational contact with them. Consequently, such aqueous systems must be treated with a corrosion inhibitor, e.g. a phosphonate, in order to prevent deterioration of such metals, e.g. pipelines.
Although water treatment chemicals can be effective at very low concentrations, a certain minimum concentration must be maintained if the aqueous system is to operate trouble-free. With the passage of time, loss of the water treatment chemical from the system occurs and replenishment is necessary to avoid the above-mentioned operational problems. On the other hand, use of excess of water treatment chemical increases operational costs. The need to balance treatment, chemical effectiveness and cost has led, therefore, to the development of methods and devices for monitoring the level of water treatment chemicals in aqueous systems.
For example, colourimetric methods are available for the determination of scale inhibitors, e.g. polycarboxylates. Colorimetric methods, however, have the disadvantage that they are subject to interference from extraneous materials. In oil field applications, for instance, interference arises mainly from iron and oil-derived organic materials.
In an attempt to overcome this interference problem, a sample-preparation (pretreatment) cartridge maybe employed, in which interfering species are removed and the water treatment chemical is concentrated. Unfortunately, however, such techniques can result in loss of the water treatment chemical being determined due to competition from the organics for adsorption sites on the cartridge. Such methods are time consuming, lack robustness and the required sensitivity (limits of detection only 1-2 ppm). In addition they require a certain amount of expertise in order to be used effectively to conduct the required determination.
More recently, immunological methods have been developed for the determination of organic compounds.
Immunological methods for determining proteins, cells, hormones, vitamins, drugs and mycotoxins etc. have been known for many years, and have been widely reported in the literature. In such methods, an animal, often a mouse or rabbit, is immunized, either with an analyte or a protein-analyte conjugate. The antibodies produced by the animal are then used, in the form of an immunoassay, to determine the analyte. These methods are based upon the specific reaction between the analyte and the antibody.
The immunoassays which have been reported in the literature incorporate antibodies that have been raised to natural molecules. Recently, however, EP 260829A, has disclosed novel mono- and polyclonal antibodies which are reactive with chlorinated phenols, especially pentachlorophenol. The antibodies can then be used to identify and assay pentachlorophenol, which is widely used as a pesticide and preservative.
We have now succeeded in applying an immunoassay method to the detection of water treatment polymers in aqueous solution, to provide a determination method which is sensitive, specific, rapid, robust and which can be operated by relatively inexperienced personnel--this has not been achieved by such methodology before the present application.